Question

Show that:
tan 10° tan 15° tan 75º tan 800 = 1​

Answer 1

Answer:

tan800°= tan(90*8+80)=tan 80°=cot10°

therefore,

tan10°tan15°tan75°tan800°

= tan10°tan15°tan75°cot10°

now, wkt, tan10°*cot10°= 1 ,

therefore,

1*tan15°*tan75°

also, tan15°= cot75° or, u may also write tan75°=cot15°

= 1*cot75°*tan75°

=1*1

=1

hence proved!